In general, filters are devices that filter contaminated raw water to generate drained clean water, and are gradually being made large in order to filter the waters of a wide river, industrial wastewater effluent, and so on.
Among these filters, the representative filter is a pore controllable fiber (PCF) filter. The PCF filter employs fiber yarns such as filament yarns that are bundled up and disposed on a path of flowing water, as a filter material. This filter material is called a fiber filter material. When the fiber filter material is used, pores formed by filament yarns can be easily adjusted under physical control, so that the PCF filter has good filtration performance, and is easily cleaned to guarantee a long effective lifetime.
In particular, the PCF filter has turned out to have an excellent effect on removal efficiency depending on particulate size, removal efficiency of suspended solids, and so on, as compared to other filters.
The PCF filter has the fiber filter material twisted around a porous tube, thereby forming fine pores.
Here, in the case in which the fiber filter material is short, twist tension is uniformly transmitted to the fiber, so that filtration layers of all the upper, middle and lower parts of the fiber are densely formed to make the quality of filtered water good. In contrast, in the case in which the fiber filter material is long, twist tension is not uniformly transmitted to all of the upper, middle and lower parts of the fiber, so that the tension of the middle part becomes weak, and thus the filtration layers are loosely formed causing the filtration performance to deteriorate.